1. Field of the Invention
The invention relates generally to safety inspections and requalification of transport arrangements. More specifically, the invention relates to a method and arrangement for the inspection and requalification of tank cars and the like type of cargo-carrying vehicles adapted to transport commodities including regulated and un-regulated materials.
2. Description of the Related Art
In order to improve the level of safety and security with which hazardous materials, as defined by the U.S. Department of Transportation (DOT) can be transported from one place to another, it has been proposed to increase the requirements for the qualification and maintenance of tank cars which are used to transport such materials along the rail systems of the country. These requirements, while initially appearing to cover essentially all aspects of the inspection process, still leave many stones unturned. For example, even though the Department of Transportation has set forth requirements specifying the types of tests which are deemed necessary for tank car carrying regulated commodities (i.e. as set forth in 49 C.F.R xc2xa7xc2xa7180.501-180.519), the actual manner in which the tests are to be carried out has not been defined in terms sufficiently specific to detail just what type of tests are required, how these tests need to be actually carried out to ensure that all of the features and structures which tend to be at high risk, are examined in a proper manner and how data derived from these tests should be evaluated and interpreted.
In other words, a worker skilled in the art of inspecting tank cars, even with many years of experience, would need guidance as to the totality of parameters to test, such as the number of sites to examine or the equipment or tests to be implemented, as well as acceptance criteria conservatively correlating the conditions observed during the inspection to an acceptable operating condition at the end of an inspection cycle term. For example, conventional testing methodology such as hydrostatic testing detects only through-wall cracks and some tanks actually fail shortly after being hydro-tested. Further, it has been found that the inspection cycle which is used in connection with the inspections has not been developed with any consideration as to the actual risk of failure, and the data which is gleaned from even relatively detailed inspection is not used/analyzed in a manner which would lead toward tank car safety.
This shortcoming is evident in the regulatory guidance provided for the inspection of linings and coatings of rail cars. Generally, linings are sheets of material, such as laminated material, glass, or fused metal, applied to the interior of a tank car to act as a barrier between the base metal and the commodity. Coatings are any paint type protective covering applied in one or more coats to the interior of a tank car to act as a barrier between the base metal and the commodity.
Appendix B to DOT-E 12095, xc2xa7180.509(i)(Nov. 16, 1998 version), Alternative Tank Car Requalification Program, provides a listing in Attachment A of materials considered corrosive to carbon steel tanks or service equipment including for example, various types of acids, such as hydrochloric acids and sulfuric acids.
For example, 49 C.F.R xc2xa7180.509(Oct. 1, 1999 edition) states:
(i) Lining and coating inspection and test. When this subchapter requires a lining or coating, at a minimum, each tank car facility must inspect the lining or coating installed on the tank car according to the inspection interval [sic: interval,] test technique, and acceptance criteria established by the owner of the lining or coating in accordance with paragraph (c)(3)(iii) of this section.
Similarly, 49 C.F.R xc2xa7180.509(c)(iii)(A)(Oct. 1, 1999 edition) states, in part:
(A) When a lining or coating is applied to protect the tank shell from the lading, the owner of the lining or coating shall determine the periodic inspection interval, test technique, and acceptance criteria for the lining or coating.
Likewise, the Alternative Tank Car Requalification Program, Appendix B to DOT-E 12095, xc2xa7180.509(i)(Nov. 16, 1998 version), states in part:
(1) Each lining or coating owner shall ensure for the qualification of a lining or coating used to protect the tank from a material listed in Attachment A of this alternative program (i.e., materials corrosive to the tank). The owner of the lining or coating shall establish and maintain a record of the service life of the lining or coating and commodity combination. Before Jul. 1, 2006, the owner of the lining shall use their knowledge of the lining or coating and commodity pairing to establish an appropriate inspection interval. After Jul. 1, 2006, the owner of the lining shall use the information in these records to determine the appropriate inspection interval for each lining or coating and commodity pairing . . .
(2) The owner of the lining or coating shall provide the test method and acceptance criteria for the lining or coating to the tank car owner and to the person responsible for qualifying the method or coating.
There is, accordingly, a need for a systematic method to compile, analyze, and record information regarding a tank car lining or coating and service environment in a form which will enable the condition of the tank car lining or coating status inspected to be tracked over a period of time to permit an accurate estimation of lining or coating condition at any given time. It is therefore evident that there is a need for some form of highly detailed instructions sufficient to enable those skilled in the art to perform an inspection of the tank car lining or coating is required.
The invention enhances the use, lease or sale of the units, with a high degree of confidence by providing a method of inspecting DOT specification tank cars, American Association of Rail (xe2x80x9cAARxe2x80x9d) regulated tank cars and like type vehicles which are used to transport commodities including both regulated (e.g. hazardous) and un-regulated materials that, at the very least, meets and/or exceeds currently imposed federal government standards and provides a level of certainty with respect features and structures that tend to be at high risk.
As will be appreciated from the preceding and following disclosure, a first aspect of this invention resides in a test procedure for inspecting a vehicle adapted to transport commodities. This test procedure includes steps of inspecting a lining disposed in a tank of a tank car and comparing at least one of cracks, blisters, and corrosion conditions on the liner with predetermined models, wherein the predetermined models convey a discrete range of severity levels of the cracks, blisters, and corrosion conditions. Based on this comparison, a severity level for such compared condition(s) are determined and recorded. In an aspect thereof are also included the steps of cross-referencing the compared condition severity level with indices indicative of the corrosiveness of a commodity to be transported in the tank to determine if lining repair is required, wherein the indices indicate a repair disposition if any one of the cracks, blisters, and corrosion exceeds a predetermined minimum threshold for a specified commodity corrosiveness. Accordingly, an accept or repair disposition to the lining is assigned.
In another aspect thereof, following inspection of the lining and determination and recording of a severity level for each of the compared conditions, a percentage of lining complete extended life cycle for a lining inspected may be determined and may be used to equate the combined defect severity level of a plurality of the compared conditions to one of a plurality of discrete lining condition values. The combined defect severity level may include a combination of any of the defect conditions, such as cracking and corrosion.
Still another aspect of the invention includes a method of standardizing a test procedure for inspecting a vessel adapted to contain commodities, including defining at least one defect type, defining a plurality of defect severities within the defect type, and generating a model of each of the defect severities within the defect type. Each of these models is then correlated to a corrosiveness of a transported commodity to determine a repair disposition of the lining in relation to the models. In an aspect thereof, additional steps of defining a plurality of defect types including at least two members selected from the group of cracks, blisters, corrosion, dry film thickness, and discoloration and defining a plurality of defect severities within each of the plurality of defect types are performed. A model of each of the defect severities within each of the plurality of defect types is generated and each of plurality of defect types is correlated to a corrosiveness of a transported commodity to determine a repair disposition of the lining in relation to the models.